An in-depth look into PTSD-depression comorbidity: A longitudinal study of chronically-exposed Detroit residents

- A bidirectional longitudinal association found between MDD and all PTSD clusters.
- Hyper-arousal was the PTSD cluster most strongly associated with MDD across time.
- Different PTSD clusters were dominant in predicting MDD at different time points.
- Female gender was a risk factor for MDD and all 3 PTSD symptom clusters across time.
- Men and women differed in the temporal pattern of MDD-PTSD comorbidity across time.

BackgroundAlthough PTSD-major depressive disorder (MDD) co-morbidity is well-established, the vast majority of studies have examined comorbidity at the level of PTSD total severity, rather than at the level of specific PTSD symptom clusters. This study aimed to examine the long-term associations between MDD and PTSD symptom clusters (intrusion, avoidance, hyperarousal), and the moderating role of gender in these associations.Methods942 residents of urban Detroit neighborhoods were interviewed at 3 waves, 1 year apart. At each wave, they were assessed for PTSD, depression, trauma exposure, and stressful life events.ResultsAt all waves, hyperarousal was the PTSD cluster most strongly correlated with MDD. For the full sample, a reciprocal relationship was found between MDD and all three PTSD clusters across time. Interestingly, the relative strength of associations between MDD and specific PTSD clusters changed over time. Women showed the same bidirectional MDD-PTSD pattern as in the entire sample, while men sometimes showed non-significant associations between early MDD and subsequent PTSD clusters.LimitationsFirst, our analyses are based on DSM-IV criteria, as this was the existing edition at the time of this study. Second, although this is a longitudinal study, inferences regarding temporal precedence of one disorder over another must be made with caution.ConclusionsEarly identification of either PTSD or MDD following trauma may be crucial in order to prevent the development of the other disorder over time. The PTSD cluster of hyper-arousal may require special therapeutic attention. Also, professionals are encouraged to develop more gender-specific interventions post-trauma.